Cholera in war-torn South Sudan has spread with at least 39 dead since the outbreak was declared last month, the World Heath Organization (WHO) said on Tuesday.

A total of 1,212 cholera cases including 39 deaths have been recorded, according to WHO figures, with the highly contagious infection spreading from the capital Juba to neighboring Jonglei state, one of the worst-affected areas by the 19-month civil war.

South Sudan's health ministry said the first case was tracked back to a UN camp in the capital Juba on May 18.